Well I used this schematic which I think I wired up right
(http://www.imghst.com/uploads/reruss4/SNES_5.JPG)
But when I plugged in my LPT and USB (Ext power) I could only press B and ALL the buttons pressed. When I disconneced from USB ground being only LPT ground , all the buttons freak out , ect ect.
Now I wondeirng if this schematic -
(http://www.imghst.com/uploads/reruss4/powersupply.gif)
Would be best , connecting 1 diode on teh LPT power pins , and one on the USB power wire and running to the controllers? basicly like what they show.
In case you're wondering I'm using this multitap that has 5 ports
(http://www.imghst.com/uploads/reruss4/TribalTap.jpg)
It sounds like a wiring fault to be honest. The first diagram you posted up looks correct, with the clock, latch and data lines in the correct place. If you have a multimeter, check the wiring by buzzing it through. If you don't have a multimeter, consider buying a cheap one that can test voltage and continuity/resistance.
The diodes are there to slurp power from the parallel port (which incidently, isn't designed to provide power). You should not need to connect those diodes to the parallel port, as you're providing power via another route (via USB).
Having the ground connected at both USB and printer port is important, as the power and signalling are effectively coming from different places. Some USB ports pull power from a different part of the power supply to the rest of the system, so this can also upset things if you do not ground properly.
I had the same problem. Turned out one of my solder lines were touching another one on my pcb. Check your wiring.
I doen tore it all apart , no board this time , gonna do just wires so I can check everything easier.
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Well I just got done doing the new one without a board to go on , works fine , no USB power added yet.
Yeah, sounds like the board was connecting things together in a way you hadn't expected. When you're doing mods like this, it's best to disable (or remove) the existing circuitry to ensure that it's not going to cause you difficulties.